1. Field of the Invention
The present invention relates to an output method and an apparatus employing such a method which requires a relatively small memory capacity in order to output information received from a host computer as high-density data.
2. Description of the Related Art
Output apparatuses such as laser beam printers are generally used to output data from computers. Laser beam printers of low density, e.g. 300 dpi, have been increasingly employed because of their quiet operation, reasonable price and compact size.
Recently, the development of a higher-density printer engine unit has been undertaken in order to further upgrade the print quality. A high-density printer engine of 600 dpi has now been developed. A printer controller for such a printer engine analyzes printing information sent to it and, according to the analysis, develops the printing information over the bit map memory, at a designated density. In the known art, it is required for the printer controller to have a bit map memory capacity corresponding to the print density of the printer engine connected thereto. For example, the memory of the controller connected to a printer engine of 600 dpi is required to be four times as large as that of the controller connected to a printer engine of 300 dpi.
Since a controller for high-density printing (600 dpi) must employ a bit map memory four times as large as that employed by a controller for low-density printing (300 dpi), a high-density (600 dpi) laser beam printer employing such a controller and engine becomes rather large and expensive, especially in a situation where color or half-tone images are to be formed.
It is an object of the present invention to solve the above-mentioned problems by providing an output method and an apparatus wherein data received, e.g. from a host computer, is analyzed, and wherein, according to the analysis, one page of the data of text description is divided into portions (or bands) to be serially developed as a high-density image (600 dpi) on the bit map memory (band processing) and to be serially printed, and one page of the data of graphic description is developed as a low-density image (300 dpi) on the bit map memory and is smoothed before output.
Another object of the present invention is to provide an output method and an output apparatus wherein highly-defined printing can be performed by a high-density (600 dpi) laser beam printer employing a bit map memory having the same capacity as the bit map memory employed in a conventional printer controller of low-density printing (300 dpi).
Still another object of the present invention is to provide an output method comprising the steps of: analyzing print data, e.g., from a host computer, to determine whether it is text data or graphic data; developing text data as dot patterns of high resolution; and developing graphic data as dot patterns of low resolution.
A further object of the present invention is to provide an output apparatus comprising: an analyzing means for analyzing print data inputted thereto; and a developing means which, according to the analysis by the analyzing means, develops test data as dot patterns of high resolution and graphic data as dot pattern of low density.
Further objects, features and advantages of the present invention will become apparent in the following description of the preferred embodiments with reference to the attached drawings.